This invention relates to circuit board test fixtures and, more particularly, to a snap-in retainer for a test probe to be used with such a fixture.
Circuit boards are commonly tested by placing them in a test fixture and using one or more test probes at predetermined locations relative to the circuit board to evaluate circuit conditions at those locations. Toward that end, the test fixture typically includes a plate which is fixed relative to the circuit board. The plate is formed with a plurality of openings at various locations in registration with circuit board locations at which testing is to be done. The test probes are inserted through selected ones of the openings to effect the desired measurements. In the past, holding a test probe in an opening has been done in different ways. For example, it is known to press fit the test probe into an opening. With such an approach, it is difficult to assemble, remove and replace the test probe. It is also known to press fit the test probe into a retainer block and screw the retainer block to the test fixture plate. With this arrangement, tools are required to install and remove the test probe and it is also time consuming. In addition, both of the aforedescribed arrangements provide a risk that the test probe can be damaged when it is press fit into either the test fixture plate or the retainer block. It would therefore be desirable to provide a retainer for a test probe which overcomes the aforedescribed disadvantages.
In a particular application, the test fixture plate has a large number of openings closely spaced in a limited area. It is also required to move the test probes from opening to opening. The use of the aforedescribed arrangements are unsuitable for such an application, since the press fitting of the test probe into a plate opening presents obstacles to relocation of the test probe and the use of a retainer block takes up excessive space and is time consuming to move. It would therefore be desirable to provide an improved retainer which can be quickly moved from opening to opening without the use of any tools.